Abstract
For scalable quantum communication and networks, a key step is to realize a quantum repeater node that can efficiently connect different segments of atom-photon entanglement using quantum memories. We report a compact and hardware-efficient realization of a quantum repeater node using a single atomic ensemble for multicell quantum memories. Millisecond lifetime is achieved for individual memory cells after suppressing the magnetic-field-induced inhomogeneous broadening and the atomic-motion-induced spin-wave dephasing. Based on these long-lived multicell memory cells, we achieve heralded asynchronous entanglement generation in two quantum repeater segments one after another and then an on-demand entanglement connection of these two repeater segments. As another application of the multicell atomic quantum memory, we further demonstrate storage and on-demand retrieval of heralded atomic spin-wave qubits by implementing a random access quantum memory with individual addressing capacity. This work provides a promising constituent for efficient realization of quantum repeaters for large-scale quantum networks.
Highlights
The realization of long-distance quantum communication and large-scale quantum networks is one of the primary goals in quantum information science [1,2]
A millisecond lifetime is achieved for individual memory cells after suppressing the magnetic-field-induced inhomogeneous broadening and the atomic-motioninduced spin-wave dephasing. Based on these long-lived memory cells, we achieve heralded asynchronous entanglement generation in two quantum repeater segments one after another and an on-demand entanglement connection of these two repeater segments. As another application of the multicell atomic quantum memory, we further demonstrate storage and on-demand retrieval of heralded atomic spin-wave qubits by implementing a random access quantum memory with individual addressing capacity
We demonstrate entanglement connection of these two repeater segments on the quantum repeater node realized with a single multicell atomic quantum memory (MAQM) by projecting the stored spin-wave modes onto a Bell state
Summary
The realization of long-distance quantum communication and large-scale quantum networks is one of the primary goals in quantum information science [1,2]. Compared with the realization of the quantum repeater node with two distinct atomic ensembles [12], this realization is more compact and hardware efficient, less vulnerable to environmental noise, and more convenient for the manipulation of information stored in different memory cells. As another application of the MAQM with long coherence time, we further demonstrate a random access quantum memory (RAQM) for states of heralded spin-wave excitations through individual addressing of different memory cells. Our experiment provides a compact and hardware-efficient implementation of the quantum repeater node, which is a key element for future large-scale quantum repeaters and quantum networks
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